Global circulation of Mars’ upper atmosphere

Science ◽  
2019 ◽  
Vol 366 (6471) ◽  
pp. 1363-1366 ◽  
Author(s):  
M. Benna ◽  
S. W. Bougher ◽  
Y. Lee ◽  
K. J. Roeten ◽  
E. Yiğit ◽  
...  

The thermosphere of Mars is the interface through which the planet is continuously losing its reservoir of atmospheric volatiles to space. The structure and dynamics of the thermosphere is driven by a global circulation that redistributes the incident energy from the Sun. We report mapping of the global circulation in the thermosphere of Mars with the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. The measured neutral winds reveal circulation patterns simpler than those of Earth that persist over changing seasons. The winds exhibit pronounced correlation with the underlying topography owing to orographic gravity waves.

1996 ◽  
Vol 39 (3) ◽  
pp. 224-228
Author(s):  
N. V. Bakhmet'eva ◽  
V. V. Belikovich ◽  
E. A. Benediktov ◽  
V. N. Bubukina ◽  
N. P. Goncharov ◽  
...  

2016 ◽  
Vol 121 (2) ◽  
pp. 1483-1502 ◽  
Author(s):  
Cao Chen ◽  
Xinzhao Chu ◽  
Jian Zhao ◽  
Brendan R. Roberts ◽  
Zhibin Yu ◽  
...  

Eos ◽  
2015 ◽  
Vol 96 ◽  
Author(s):  
Eric Betz

Deep convective objects such as the plumes in thunderstorms can trigger gravity waves, which disturb the wind and temperatures hundreds of kilometers above Earth's surface.


2020 ◽  
Author(s):  
Jean-Yves Chaufray ◽  
Majd Mayyasi ◽  
Michael Chaffin ◽  
Justin Deighan ◽  
Dolon Bhattacharyya ◽  
...  

<p>The recent observations performed with the high-resolution “echelle mode” by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission indicated large deuterium brightness near Ls=270°. The deuterium brightness observed at the beginning of the mission, when Mars was close to its perihelion show brightness ~ 1 kR much larger than the first deuterium detection from Earth ~ 20-50R in 20-21 January 1997 (Ls = 67°). This low brightness of the deuterium emission is consistent with the lack of deuterium observation with the echelle mode of IUVS at solar longitudes around aphelion (Ls = 71°). During southern summer (Ls = 270°), especially near the terminator, the Lyman-α emission observed at 121.6 nm with the “low resolution mode” presents some vertical profiles that were not reproducible with models including only the emission from the thermal hydrogen population. In this study, we investigate the possibility to derive quantitative information on the D/H ratio at Mars from the vertical Lyman-α profiles observed with the “low resolution mode”, and the main limits of the method.</p>


2004 ◽  
Vol 348 (2) ◽  
pp. 609-624 ◽  
Author(s):  
C. P. Burgess ◽  
N. S. Dzhalilov ◽  
T. I. Rashba ◽  
V. B. Semikoz ◽  
J. W. F. Valle

Science ◽  
2020 ◽  
Vol 370 (6518) ◽  
pp. 824-831
Author(s):  
Shane W. Stone ◽  
Roger V. Yelle ◽  
Mehdi Benna ◽  
Daniel Y. Lo ◽  
Meredith K. Elrod ◽  
...  

Mars has lost most of its once-abundant water to space, leaving the planet cold and dry. In standard models, molecular hydrogen produced from water in the lower atmosphere diffuses into the upper atmosphere where it is dissociated, producing atomic hydrogen, which is lost. Using observations from the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft, we demonstrate that water is instead transported directly to the upper atmosphere, then dissociated by ions to produce atomic hydrogen. The water abundance in the upper atmosphere varied seasonally, peaking in southern summer, and surged during dust storms, including the 2018 global dust storm. We calculate that this transport of water dominates the present-day loss of atomic hydrogen to space and influenced the evolution of Mars’ climate.


1990 ◽  
Vol 138 ◽  
pp. 469-487
Author(s):  
Oddbj⊘rn Engvold

The requirements and conditions for high resolution imaging and polarimetry of the Sun are reviewed. Various methods and techniques are discussed for image stabilization and sharpening in solar observations. The new solar facilities in the Canary Islands in particular are frequently reaching diffraction limited resolution and yield new insight in the structure and dynamics of the solar atmosphere. Future ground based telescopes like THEMIS and LEST, as well as planned solar missions in space will trigger a next advance in solar physics.


2019 ◽  
Vol 55 (4) ◽  
pp. 303-311
Author(s):  
Y. A. Kurdyaeva ◽  
S. N. Kulichkov ◽  
S. P. Kshevetskii ◽  
O. P. Borchevkina ◽  
E. V. Golikova

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